Research On Flexible Cable Batteries And High Voltage Batteries Based On Carbon Nanotube Film

With the rapid development of Internet technology,a variety of portable and wearable electronic equipment has been developed.The flexible electronic equipment requires the power system that can be bent,folded and other operations.In addition,long life of the batteries also should be provided.However,traditional LIBs cannot be bent or folded for metal foils were using as current collector,which reduces the interface adhension between the active material and current collector.In order to solve the questions,carbon nanotube macro-films(CMFs)were used as the electrode collectores for anode and cathode,LiCoO2 and Li4Ti5O12 were coated on the surface of the CMF respectively,and the assembled cable-type battery showed a good flexibility;which was can be bent,winded or knotted.However,the flexible battery showed a lower operating voltage(2.5 V),which can not be applied on wearable electronic devices dieectly.Therefore,the surface of the CMFs were modified with(heptadecafluoro-1,1,2,2-tetradecyl)trimethoxysilane to form a siloxane layer,and NFSC was used to connect conductive channel between the surface of the formed nanostructure and the surface of the CMFs.In addition,impurities on the formed nanostructure and CMF were removed through carbonization treatment with high temperature.Then,graphite was coated on the surface of the composite film to improve the operating voltage of the full battery.In this thsis,the fluorinated surface of the CMF were characterized by infrared spectroscopy.And the surface morphology of the composite films after electrodeposited NFSC was checked by Field scanning electron microscopy(SEM).The relevant elements of the composite film were characterized by X-ray diffraction and X-ray photoelectron spectroscopy.The main results of this studies were shown as follow:1)The assembled cable type battery device can be bent,twisted or knotted without changing their electrochemical performance,which can be using as wire and energy storage with double functions.Further,the electrochemical cycling performance and rate performance of the calbes are stable,and displayed a high power density of 125 Wh kg-1,power density of 370 W kg-1and a capacity density of 0.98 mAh cm-1.2)The surface of the CMF formed a layer of nanosiloxane film through fluorinated method by(heptadecafluoro-1,1,2,2-tetradecyl)trimethoxysilane.The conductive channels were connected between the surface of fluorinated layer and the surface of CMF through NFSC electro-deposited on the composite film.After carbonized treatment at high temperature,and then coated graphite on the composite film,a full battery with high working voltage can be obtained.(3)The voltage of LCO-CMF / Graphite-NFSC-FCMF(carbonization)full battery is about 3.7 V,which increased sharply comparing to the working voltage of LCO-CMF / LTO-CMF full batteries.In addition,the specific capacity and the retention rate of the full batteries are 94.1 mAh g-1 and 93.2 % respectively after cycling 100 times.The formed electrolyte-phobicity and conductive CMF is the main factors to increase the working voltage of the batteries.